Thermostatically controlled mixing valve



July 15, 1952 P. G. TAccHl THERMOSTATICALLY coNTRoLLED MIXING VALVE:

2 SHEETS-SHEET 1 Filed May '7, 1951 I iNVENTop.

eY/C'LM-ym, A mM-- l l l v ik... AGENTS.

July l5, 1952 P. G. TAccHl THERMOSTATICALLY coNTRoLLED MIXING VALVE .2 SHEETS- SHEET 2 Filed May '7, 1951 mss;

l v I lNvEN-rn QM',

u AGEN-rs Y Patented July 15, 1952 f UNITED 2,603,420 x ,Y i, THERMOSTATICALLY CONTROLLED v MIXING VALVE Percy Georg'e'racchi, LongaNoi-.th Curry,

' Taunton,- England Appiicaiion May fi, 1951, serial No; ,224,865

In' Great Britain October f7, 1948 claim.Y (c1. 236412)v This invention relates to thermoplastically con trailed mixing valves of the kindv in which two-or more nuids at differing temperatures arev supplied to e, mixing chamber in which mixture of the tiuids is effected, thevalve being'provided With a thermally responsive element adapted to Change its shape in response to variationY of temperature lof the mixture and arranged to actuate valve means comprising a movable valve member -or controlling the `relative proportions of the uids supplied so that the resultant fluid mixture is maintained ati a predetermined giventemperature.

A number of mixing valves of the foregoing kind haveV already been proposed inl which one end of the thermally responsive element, is conenected tothe valve member,v the other end of the vthermally responsive element being connected to an adjusting member mounted movably on the valve 'bodyand provided for' the purpose of adjusting therelative proportions of the fluidsjat a given temperature. In such an arrangement the adjusting movement is transmitted from the adjusting member through the thermally ,responsive element to' the valve,'member'sou that thepossibility arises of the thermally responsive 'element which is necessarily of. relatively'delieate construction, being strained `or otherwise damaged with such an arrangement. f Y

Further, with this arrangement, owing tothe flexible nature of the thermally responsive elenient' and the frictional resistance offered bythe valve member there arises lost motion between the adjusting member and the valve member which will; have an adverse effect von the accuracy oi setting of the adjusting member. l -fThepresent invention hasffor itsobje'ct'the preivisionV of an improved arrangement ini which th-foregoing disadvantages ofthe known con# stiuc'tion above referred tois V'avoided in which a variation of vvpressure ofone "orlmore ofthe'fiuidgsupplied to the valve does'fnot of itself vdirectlyv interfere with the eiie'ctive' opera- 'ti'on of thev thermally responsive element and of the valve means so that' the uid mixture is still maintained. at the predetermined` givenitemperat-ulferyf f 4i, ,1 z. According to the present krinvention I provide 4a--inixing'1valvecomprising a body ncludi'ngka Dhlrality f ofVv Supply openings each fori-supplying one-idf the fluids' to be mixed, afni-xingk chamber in which mixturepoifthe fluidsris-effectedua dis-V charsei'openineior diSch-areinethe mixture .from .thefmeiI-lg .almbelz @thermally iresponsiveaelef men-t 2id-@Pied fio-,Change `its; Shape; in? response yto variation of temperaturey of the mixture, and being arranged so as to permit .of themixltiire nowing yin contact therewith, one end of said thermally'responsive element being connected lto thefbody andthe other endbeing'operatively connected to a valve member mounted within the casing andhaving one or more' ports adapted to' control the supply of one or more fluids to the mixing chamber, thearrangement being' such that thev valve member is displaced inconsequence of change of shape of the thermally responsive element to' vary the flow of theY fluid controlled by saidn ports, and" the 4latter beingso arranged' in relation to the direction of operative displacement of the valve member as to ensure that the pressure exerted by the iiuid when passing through said ports does not produce lany substantial ref' i sultant'thrust-actihg in the direction of operative displacement ofl said valve memberso Aas to vdise` place the'valv member or thermally responsive element,l and means being provided for adjusting the operation of the valve, so as to vary'the relative'l proportions of the mixture, saidadjusti ingmeans .operating dire'etlybetween the valve body. and the valve member sothat the'adjusting movement be( transmittedV ,directly tolthe valve `member f without passing through the thermally responsive element. A y

-In a rmore specificform, .the invention consists ina-,mixing,valvewhich is mounted for'bot'h rotationaland axial movement rand Va AScrew threaded connectionisfprovided between the valve member andthe vbody :adapted yto prevent the valve-Y .member being :displaced out ofr its given operativelfzposition undercluid pressure, acting onrthe edges o'i-the valve member ports; v "'A'further object' o'f the present -inventionds to provide certain improvements whereby the siz'e 'of the valve may be reduced, and consequently the cestflwithout sacri-nceof the leiiiuzie'rmy 'of the Van/ m y. n, According to' a= further-feature `of the'pi'esent invention the ports in the'cylindrical valve inem'-Y ber and the seating member are in the form-of elongated openings'or rows of openings, the major axiszof anelongated opening' ofthe line of riv of openings beine incifnied tothe axial'direction in Whip ,tlie'valv'e member moves, the direction oi.v inclination being the same `for all .the ports softhat'V therot'atonal component of. the relative movement between thefvalve' `member vand its seating. is, utilized inv 1displacing ti1e fopeningsv ,vor rows 0f Openings 0n the valve member relative@ the corresponding openings inthe-seating in, va

. 3 direction transverse tov the major axes of the opening or the lines of rows of openings.

The invention is illustrated in the accompanying drawings, wherein:

Figure 1 is a sectional side elevation of one form of mixing valve constructed in accordance with the present invention.

Figures 2 and 3 are sectional views on the lines 2-2 and 3 3 respectively of Figure 1.

Figures 4 and 5 are sections through the valve member and seating and showing two forms of an improved type of valve member with an arrangement of ports which provides a complete valve of smaller dimensions without loss vo eiciency.

Referring to the drawings, the mixing valve there illustrated is intended for use in 'obtaining a supply of hot water from a supply of steam and cold water and such valve comprises a body I of substantially cylindrical configuration provided at one end with` a number of attachment iianges II for securing it to a convenient support, the body at a position spaced from such flanges being formed internallywith a pair of iluid supply passages I2, I3 of annular configuration spaced apart axially of the body and separated by a relatively thin thermally conducting wall I4 forming part of the body. One of these passages, for example, the passage I2, is provided in the peripheral wall of the body' with a supply opening I5 for connection to a water supply pipe, the other passage, conveniently the passage I3, being provided similarly with a supply opening I6 for connection to Ya suitable steam supply pipe.

The thermally conducting wall serves tov permit of a certain initial transfer of heat from the steam to the cold water for the purpose above indicated'. This wall may be of corrugated or finned configuration so as to increase its thermal conductivity for this purpose. Also the wall serves to cause the deposit of any solid matter from4 the heated water before it reaches the ports and-valve member.

The inner wall of each of the annular pasv sages I2, I3 is constituted by a sleeve-like valve seating member I'I which is formed at positions corresponding to each of the annular passages I2, I3 withfa number of circumferentially spaced openings I8 (or if desired with a single continuous opening of part-circular configuration), which openings serve to admit the two fluids, namely, steam and water, to a valve'member I9 of hollow cylindrical form mounted rotatably within the seating member I1 so as to be influid-tight engagement therewith, the valve member I9 being capable 4also of being Ydisplaced axially through ,a limited distance relative to the seating member. v.

Thisyalve-member I9 is provided with two sets of ports 20 and 2I which form respectively water and steam ports and are spaced apart axially of the valve member by a distance greater than the axial spacing Vof the two sets ofv openings I8 in the valve seating and these ports 20 and 2I serve to admit uid from Ythe corresponding openings I8 into the' interior of the valve member which interior serves as a mixing chamber indicated at 22 in' which thevtwo fluids.: i. e. the steam and water are mixed together; It will beappreciated that the axialspacing of the valve member ports could be less'than the axial spacing of the ports in the seating (as is the case in Figures 4 and 5 hereinafter described). In eithercase the dilerence in Vspacing may be approximately equal to the widthv of a port.-

The axial length of each set of ports 20 is preferably somewhat greater than the axial length of the corresponding opening which they control and where a single opening I8 is provided for each of the annular passages I2, I3 a single corresponding port may be provided in the valve member, but in the preferred arrangement illustrated the four circumferentially spaced openings I8 are provided for each annular passage with a corresponding number of similarly spaced ports 29 and 2I, for example, as shown in Figure 2.

The mixing chamber 22 formed by the hollow interior of the valve member communicates with a' chamber 23 for receiving a thermally responsive element which chamber is formed integrally with the end of the body adjacent the attachment ange II and the end of this chamber' which is remote from the valve member I9 is open and communicates with the interior of a mixture discharge member 24 mounted on the adjacent end of the body I0 in uid tight engagement therewith, the member being Vprovided at one side with a radially directed hot water discharge orifice 25 through which the hot waterv formed by the mixture of the steam and cold water is discharged.

Conveniently the discharge member is mounted adjustably on the body by providing the member with a number of spaced peripheral lugs 26 adapted to be secured to the attachment flange II in different angular positions by forming the flange I I with a large number of circumferentially spaced holes 21 to receive xing screws 28 as shown in Figure 3, so that the discharge member can occupy different angular positions relative to the body I0 according to the direction in which it is desired to discharge the-mixed uid when the apparatus is first set up. y The discharge member 24 is formed centrally with a tubular bearing portion 29 which extends axially into the interior of the thermostat chamber, such tubular portion having its inner end of reduced section and substantially square configuration externally as indicated at 30 in Figure 3, upon which is non-rotatably mounted a sleeve 3I formedfperipherally with Ya slot 32 in which is anchored the inner end of a spirally coiled length of bi-metal strip which forms the thermally responsive element 33. The outer end of thisstrip is anchored to a lug 3IIv formed integrally with the adjacent end of the valve mem-.- ber I9. The adjacent turns of the coiled strip are spaced apart a sufficient distance to permit of free relative movement of the adjacent turns, as well as to permit of the mixed fluid owing through the interior of the thermally responsive element between adjacent turns of the coil. The thermally responsive element 33 is providedwith a sufficientrnumber ofV coil turns as to `ensure that the outer end of the coil can move axially in relation to the inner end thereof when the valve vmember I9 is displaced axially without fear of significant distortion of the thermall responsive element occurring.

The arrangement is such that the iiuid mixture passing through the thermally responsive element chamber 23 flows between substantially the whole of the coils forming the thermally responsiveelement. which element is in the direct line of flow ofthe iluid from the mixing chamber to the discharge member, so that in the event of .achange 'of temperature occurring within the 7 body t)` with apair of fluid supply passages 5l and 52 separated by the wall53. '.The sleeve like valveiseating member 5,4 is formed with two -heliv cal'slots 55 and 56 and the valve member 51 has helically arranged slotsv 58 and 59 which coop- .erate with the slots 55 and 56 in the seating member 54. '.In FigureY 5 slots 60 andrSl are provided in the seating member 54 as in Figure 4 but'instead of slots inthe valve member 59, rows of holes 62 and 63 areV provided. Y f Y lIn both cases thev slots o r rows of holes are arranged ,helically, as shown, and with the valve in the position in which the inlet in passage 5l is fully open and the inlet in passage 52 is `fully closed. When the valve moves to the right as shown in Figures 4 and 5, inlet 5l closes :and inlet 52 opens and, duetothe helical arrangement of the openings a certain amount of relative axial movement is achieved `between the openings in the valve member and those in the seating member because of the rotational movement impartedV charge opening for discharging the mixture from the mixing chamber, a thermally responsive element comprising a length of spirally coiled bimetal strip, said body being provided internally with a hollow cylindrical valve seating, a hollow cylindrical valve member mounted within said seating so as to be rotatably and axially displace- -able relative to the seating, a valve adjusting .spindle extending from one end of the body through the centreof the bi-metal coil and into the hollow interior of the valve member, the latter being provided internally with a nut having .threaded engagement with the adjusting spindle,

fsaid bi-metal strip being connected at one end to'v the valve body and at the other end to the valve member and 'being adapted to impart rotational movement to the valve member in consequence of a change of temperature of the thermally responsive element so `that the' valve member is bothlrotatedand displaced axiallyrelative to its seating'by'reason of its threaded connection to the adjusting spindle,`said seating andvalve `member being provided each with one Yor more vports adapted in cio-operation with one another.

to control the supply of one or moreiiiuids to themixing chamber; the arrangement being such that-when the valve member is displaced axially in one or the other direction, thezsupp'lyof one iluid to the mixing chamber is increased or decreased in relation to that of another fluid, each -valvemember port extending radially thereof so that the pressure of the fluid acting on the edges 2. A valve according, to claim lvvherein the inner end of the bi-metal-coil ismounted rigidly l 'invthe seating 1in a direction *':major axes of theports'.' f

5." A mixing valve ycomprising a bodyiincludin'g 1a pluralityrof supply openings each for supplying onl a sleevel rigid with the valve body in the inf terior of which sleeve the adjusting spindle is rotatably mounted. ,l Y .t

Y ,3. A 'mixing valve comprising a bodyincluding a plurality lof supplyopenings each for supplying one of the fluids to' be` mixed, a'mixing chamber in which mixture of the fluids is effected, adischargeA member having an opening for discharging the mixture fromf the mixingchamber,l a thermally responsive element adapted to Vchange its shape in response to variation of temperature of the mixture, andbeing arranged so as tov per# mit of the mixture iiowing in contact therewith, one end of said thermally responsive element being connected to the body and the other end being operatively connected to 'a cylindrical valve member mounted `Within the body, said valve memberbeing mounted for rotational and axial displacement within a seating member'. xed in the body, said seating and valve memberxbeing provided'each with ports adapted in cooperation with. one anotherto control the supply of ilulds to the 'mixing chamber, they arrangement being suchthat when the valve member is displaced axially lin oneor the other direction thesupply of yone' fluid tothe mixing chamber is increased or. decreased in relation to that of another uid, said ports all being arranged with their; major axes inclined, in the same direction, to the direction of relative rotational movement between the valve member and its seating, so .that the rotational component of the relative movement between the vvalve member and seating isutilised in displacing the ports on the valve memberrelative to the corresponding ports in the seating in a direction transverse to the majorY axes ofthe ports. Y p

i 4. A' mixing valve comprising a body including `a plurality of supply openings each for supplying one of the uids to be mixed, a mixing chamber in which mixture of the fluids is effected, a' discharge member having an yopening for discharging the mixture fromY the mixing chamber, a thermallyv responsive element :adapted to change its. shape infresponse to variation 'ofvtemperature of the mixture, and being arranged so as to permit' of the mixture owing in contact therewith. one end .of said thermally responsive element being connected to the body'and. the other end being 'operatively connected to a'cylindrical valve member mounted Within the body,A said valve member being mounted for rotational and axial ydisplacement withinl a seating member xed'in the body, said seating and valve member being .provided each withp'o'rts adapted in cooperation @with one another to control the supply' of fluids to the' mixing chamber, the arrangement being such'thatwhenthe valvey member 4is displaced axially'in oneor the other direction the supply of one uid to the mixing chamberis increased or decreased in relationto that Voffanother iiuid, said ports comprising elongated slots Vwith their major axes extending helically, al1 'of the Y'same "hand, with respect to the axis of the valvememjber, so that the rotational component'- of 'the relative movement 'between the valve member and seating is utilised in displacing the slots onthe valve member relative to the corresponding slots transverse `to Vthe one ofthe fluids to be mixed, a mixing chamber in which mixturezoffthefluids is ee'cted..v a discharge member'havingan openingfordischarg- Y 9 ing the mixture from the mixing chamber, a thermally responsive element adapted to change its shape in response to variation of temperature of the mixture, and being'arranged so as to permit of the mixture flowing in contact therewith, one end of said thermally responsive element being connected to the body and the other end being operatively connected to a cylindrical valve member mounted within the body, said valve member being mounted for rotational and axial displacement within a seating member fixed in the body, said seating and valve member being provided each with ports adapted in cooperation with one another to control the supply of'fluids to the mixing chamber, the arrangement being such that when the valve member is displaced axially in one or the other direction the supply of one fluid to the mixing chamber is increased or decreased in relation to that of another fluid, the ports in the seating member comprising each a continuous slot arranged helically with respect to the axis of the valve member, and the ports in the valve member comprising rows of holes 10 arranged helically with respect to the axis of the valve member, so that the rotational component of the relative movement between the valve member and seating is utilised in displacing the rows of holes on the valve member relative to the corresponding slots in the seating in a directiontransverse to the major axes of the ports.

PERCY GEORGE TACCHI.

REFERENCES CITED The following references are of recordin the file of this patent:

UNITED STATES PATENTS Great Britain Apr. 16, 1947 

